This invention relates to a toner recovery device or a toner-collecting device for an image forming apparatus such as an electrophotographic copying machine, in particular, to a toner recovery device that collects the toner remaining on the surface of an image carrying member such as a photosensitive drum by using a cleaning device that drops the toner into a container.
As a toner recovery device mentioned above, a device is disclosed in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 54369/1983. This toner recovery device has a container that has a toner inlet at one end. By an eccentric rotary cam with a stepped peripheral surface, this container is deflected toward the toner inlet side as overcoming a spring force, and then the container is allowed to fall onto a small diameter area of the eccentric cam. The container is thereby repeatedly subjected to a negative acceleration wherein it's motion by spring force is stopped at the small diameter peripheral surface of the cam. However, this toner recovery device has a problem, since the motion of container by the spring force is prevented by the stepped eccentric cam to give negative acceleration to the container, the container oscillates vertically as well. Thus stable movement of toner caused by acceleration is hindered and toner tends to accumulate at the entrance of the toner inlet. Therefore, in order to contain a large amount of toner in the container, the height of the container must be large not only at the toner inlet section but also at the part which is away from this section it causes bulkiness of the image forming apparatus. Moreover, the collision to the cam causes serious wear of the cam and cam follower, resulting in poor durability of the toner recovery device and excessive noise.
There is another toner recovery device presented in Japanese Patent Publication Open to Public Inspection No. 231575/1984. This toner recovery device has a photo-sensor which detects the toner accumulated at a toner inlet, and lets a container be vibrated forcibly. For this purpose a lump of toner must be formed. Thus, since the height of the container must be increased, it is difficult to realize a compact image forming apparatus.